The present invention relates to a method for producing optical coatings by means of plasma polymerization deposition in addition to thermically evaporated coatings. Such coatings are mainly used in the field of ophtalmics where they are exposed to especially hard environmental conditions. Coatings, such as anti-reflecting coatings therefore must adhere very well to the base. It is known that the substrate must be etched or provided with a layer which functions as an adherence interface before the thermically evaporated layer or layer system with optical effects is brought onto the base. The mentioned adhesive layer may not interfere with the optical characteristics of the layer system or the lens. It must be especially transparent. This adhesive layer is especially important when used for coating plastic substrates.
It is known that such coatings are produced by depositing them with a glow discharge by means of polymerisable gases. Among experts this is known as glow discharge polymerization or plasmapolymerization. U.S. Pat No. 3,713,869 teaches that an intermideate layer used as adherence agent is deposited on a PMMA plastic substrate and then coated with a hard inorganic layer. T. Wydeven and R. Kubacki in their article "Antireflection coating prepared by plasma polymerization of perfluorobutene-2" (Applied Optics, Volume 15, No. 1, January 1976) describe a method for producing an anti-reflection layer by using the plasma polymerization-method. It is also said that the plasma polymerization can take place simultaneously on both sides of the substrate. The German application DE 22 63 480 discloses a plasma polymerization method where the coating is meant to be a protective coating being scratch-resistent and water-repelling.